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Be alert to the effects of too much caffeine

March 16, 2023 

As part of March’s Caffeine Awareness Month, HSHS St. John's wants to share how the stimulant affects our brain and body. 

The U.S. Food and Drug Administration (FDA) estimates 80% of U.S. adults consume caffeine daily. Although it can help with alertness, health experts say overdoing it can cause dangerous side effects including:

  • Increased risk of heart attack
  • Increased blood pressure
  • Insomnia
  • Skin aging and wrinkling
  • Headaches
  • Increased anxiety

One known effect of caffeine is the negative stimulation of the adrenal glands. The adrenal glands sit on the kidneys and have a role in releasing hormones when we are confronted with stress. When caffeine is consumed, these glands are stimulated to release adrenaline into the body. This can affect sleep patterns and make us less alert in the morning and throughout the day.

Caffeine is a stimulant and although it takes about 30 minutes to take effect, it can remain in your system for eight to 10 hours.

The FDA recommends no more than 400 milligrams (mg) of caffeine daily for adults; less is recommended for those who are more sensitive to the effects of caffeine and how quickly it breaks down in the body. Keep in mind, the amount of caffeine contained in foods and beverages varies widely.

  • One, eight-ounce cup of black coffee: 95mg
  • One, eight-ounce cup of green tea: 35-70 mg
  • One, eight-ounce energy drink: 50-250mg
  • One, 12-ounce can of cola: 40-50mg
  • One, eight-ounce can of energy coffee: 145mg

Caffeine is not recommended for children, and women who are pregnant, trying to become pregnant, or breast feeding. It also should not be mixed with certain medications, so talking with your health care provider about medication management is important. 

If you decide to lower your caffeine intake, drink more water to avoid dehydration and cut back gradually to avoid withdrawal symptoms such as headache and anxiety.

Be alert to the effects of too much caffeine